Enable [[Virtualization|VM hosts]] to discover new SAN storage, issue NPIV operations and do basic configuration of multipath devices.

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Enable [[Virtualization|VM hosts]] to discover new SAN storage and issue NPIV operations.

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This functionality is currently a work in progress, and this page will be updated as it is developed.

== Owner ==

== Owner ==

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== Current status ==

== Current status ==

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* Targeted release:

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* Targeted release: [[Releases/12|Fedora 12]]

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* Last updated: 2009-03-02

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* Last updated: 2009-08-05

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* Percentage of completion: 20%

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* Percentage of completion: 100%

== Detailed Description ==

== Detailed Description ==

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=== Background ===

=== Background ===

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Guest virtual machines can currently use SAN storage and multipath devices, but administrators must do the storage configuration manually using separate tools from libvirt. This feature will permit administrators to discover storage and present it to virtual machines using libvirt.

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Guest virtual machines can currently use SAN storage, but

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administrators must do the storage configuration manually using

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separate tools from libvirt. This feature will permit administrators

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to discover storage and present it to virtual machines using libvirt.

Datacenter operations are usually split along functional lines: the

Datacenter operations are usually split along functional lines: the

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facilities management team, the server administration team, the SAN

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server administration team, the SAN administration team, and others

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administration team, and others (network, etc.) not relevant to this

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(network, etc.) not relevant to this discussion. Within the server

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discussion. Within the server admin group, there are often sub-groups

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admin group, there are often sub-groups for each OS. When a new

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for each OS. When a new application is deployed the SAN

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application is deployed the SAN admins provision the storage and

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admins provision the storage and notify whichever OS team is responsible for the server to

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notify whichever OS team is responsible for the server to proceed with

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proceed with the OS install.

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the OS install.

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There may be more or less information transmitted from the SAN admins to the server admins when the storage becomes available. The minimal message is something along the lines of, "I've provisioned the LUNs, and

The libvirt APIs already permit storage discovery and pool creation. These functions will be extended to discover storage on a per-SCSI-host basis and multipath devices. The pool create and destroy functions will be extended to understand multipath and NPIV.

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The libvirt APIs already permit storage discovery and pool creation.

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These functions will be extended to discover and rescan storage on a

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per-SCSI-host basis. The node device APIs will be extended to create

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and destroy vitrual adapters using NPIV.

== Benefit to Fedora ==

== Benefit to Fedora ==

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=== TODO ===

=== TODO ===

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* Implement storage discovery

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* Implement NPIV operations

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* Implement multipath configuration

=== Completed ===

=== Completed ===

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* SCSI storage discovery is mostly complete.

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* SCSI storage discovery and rescan are complete.

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* The creation and destruction of virtual HBAs using NPIV is complete.

== How To Test ==

== How To Test ==

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Provision a new logical unit on iSCSI or fibre channel storage. Use virsh to trigger a scan for it, and confirm that it appears correctly.

Provision a new logical unit on iSCSI or fibre channel storage. Use virsh to trigger a scan for it, and confirm that it appears correctly.

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TBD: Fill in how to configure & test this

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To discover logical units on a particular HBA, create a pool for that

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HBA using:

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<code>virsh pool-create hbapool.xml</code>

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where hbapool.xml contains:

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<pre>

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<pool type="scsi">

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<name>host6</name>

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<source>

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<adapter name="host6"/>

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</source>

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<target>

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<path>/dev/disk/by-id</path>

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</target>

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</pool>

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</pre>

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=== Create a virtual HBA with NPIV ===

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Confirm that all the appropriate logical units are visible as volumes

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with:

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<code>virsh vol-list host6</code>

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After creating the pool, add a new logical unit on a target that's

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visible on that host and refresh the pool with:

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<code>virsh pool-refresh host6</code>

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and confirm that the new storage is visible. Note that the refresh

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code only scans for new LUs on existing targets and does not issue a

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LIP to discover new targets as that would be disruptive to I/O.

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=== Create and destroy a virtual HBA with NPIV ===

Issue an NPIV create call and confirm that the VM host has instantiated a new host adapter and that any storage zoned to it is usable.

Issue an NPIV create call and confirm that the VM host has instantiated a new host adapter and that any storage zoned to it is usable.

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TBD: Fill in how to configure & test this

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To create virtual HBAs using libvirt, it is of course necessary to

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have an NPIV capable HBA and switch. You can confirm that you have

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those by manually creating a new HBA by an echo into sysfs.

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The file you echo into may be in one of two places, depending on which

First, find the node device name of the HBA that's going to be used to

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create the virtual adapter. You can get a list of all the HBAs on

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your system with:

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<code>virsh nodedev-list --cap=scsi_host</code>

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For example:

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<pre>

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# virsh nodedev-list --cap=scsi_host

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pci_10df_fe00_0_scsi_host

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pci_10df_fe00_0_scsi_host_0

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pci_10df_fe00_scsi_host

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pci_10df_fe00_scsi_host_0

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pci_10df_fe00_scsi_host_0_scsi_host

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pci_10df_fe00_scsi_host_0_scsi_host_0

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</pre>

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Dump the XML for each HBA until you find the host number of the

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physical HBA you want to use:

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<pre>

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# virsh nodedev-dumpxml pci_10df_fe00_scsi_host

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<device>

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<name>pci_10df_fe00_scsi_host</name>

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<parent>pci_10df_fe00</parent>

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<capability type='scsi_host'>

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<host>5</host>

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<capability type='fc_host'>

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<wwnn>20000000c9848140</wwnn>

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<wwpn>10000000c9848140</wwpn>

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</capability>

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<capability type='vport_ops' />

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</capability>

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</device>

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</pre>

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HBAs that are capable of creating virtual adapters will have a

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capability type='vport_ops'.

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Once you know the node device name of the parent HBA, create a file

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containing XML describing the virtual HBA you want to create:

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<pre>

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<device>

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<parent>pci_10df_fe00_0_scsi_host</parent>

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<capability type='scsi_host'>

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<capability type='fc_host'>

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<wwpn>1111222233334444</wwpn>

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<wwnn>5555666677778888</wwnn>

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</capability>

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</capability>

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</device>

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</pre>

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The parent element is the name of the parent HBA as listed by virsh

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nodedev-list. wwpn and wwnn are, as you would expect, the WWNN and

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WWPN for the virtual HBA to be created. Libvirt does not do any

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validation of the WWPN/WWNN; invalid WWNs are rejected by the kernel

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and libvirt reports the failure. The error reported by the kernel is

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somewhat misleading, however:

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<pre>

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# virsh nodedev-create badwwn.xml

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error: Failed to create node device from badwwn.xml

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error: Write of '1111222233334444:5555666677778888' to '/sys/class/fc_host/host6/vport_create' during vport create/delete failed: No such file or directory

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</pre>

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To create the new virtual HBA, feed the file to virsh:

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<code>virsh nodedev-create new.xml</code>

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If the operation succeeds, you'll get a message similar to:

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<pre>

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# virsh nodedev-create dpa/newhost.xml

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Node device pci_10df_fe00_0_scsi_host_0_scsi_host created from new.xml

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</pre>

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=== Create all available multipath devices ===

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and you will see the new HBA in the OS. The create command output

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gives you the node device name of the newly created device.

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Issue the call to create all available multipath devices and confirm that they are created and usable.

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To destroy the device, use virsh nodedev-destroy:

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TBD: Fill in how to configure & test this

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<pre>

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# virsh nodedev-destroy pci_10df_fe00_0_scsi_host_0_scsi_host

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Destroyed node device 'pci_10df_fe00_0_scsi_host_0_scsi_host'

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</pre>

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<!--

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and you will see the HBA disappear from the OS.

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A good Test Plan should answer these four questions:

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0. What special hardware / data / etc. is needed (if any)?

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1. How do I prepare my system to test this feature? What packages

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need to be installed, config files edited, etc.?

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2. What specific actions do I perform to check that the feature is

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working like it's supposed to?

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3. What are the expected results of those actions?

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-->

== User Experience ==

== User Experience ==

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== Release Notes ==

== Release Notes ==

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This functionality adds the ability in libvirt to discover storage on a per-SCSI-host basis, issue NPIV operations and configure multipath devices. This enables administrators to discover, configure and provision storage for virtual machines without having to use multiple tools.

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This functionality adds the ability in libvirt to discover storage on a per-SCSI-host basis and issue NPIV operations. This enables administrators to discover, configure and provision storage for virtual machines without having to use multiple tools.

Owner

Current status

Detailed Description

Background

Guest virtual machines can currently use SAN storage, but
administrators must do the storage configuration manually using
separate tools from libvirt. This feature will permit administrators
to discover storage and present it to virtual machines using libvirt.

Datacenter operations are usually split along functional lines: the
server administration team, the SAN administration team, and others
(network, etc.) not relevant to this discussion. Within the server
admin group, there are often sub-groups for each OS. When a new
application is deployed the SAN admins provision the storage and
notify whichever OS team is responsible for the server to proceed with
the OS install.

There may be more or less information transmitted from the SAN admins
to the server admins when the storage becomes available. The minimal
message is something along the lines of, "I've provisioned the LUNs,
and you should be able to see them now. The LUNs are 27, 28, 29 and
53." The server admin may not know what targets or hosts the new
storage is accessible through, but a rescan of all host adapters will
show up new logical units of the size requested with numbers 27, 28,
29 and 53 on some target on some host, and the server admin assumes,
usually reasonably, that these logical units are the new storage.

While libvirt is currently capable of using SAN storage, it lacks the
ability to trigger scans for new storage and create virtual host
adapters using NPIV. The OS admin team that manages the VM host must
get involved to get the VM host to recognize the new storage. Giving
libvirt the ability to manage storage allows the OS admin team
responsible for the guest OS to complete the VM build out itself.

Implementation

The libvirt APIs already permit storage discovery and pool creation.
These functions will be extended to discover and rescan storage on a
per-SCSI-host basis. The node device APIs will be extended to create
and destroy vitrual adapters using NPIV.

Benefit to Fedora

Administrators will be able to provision storage for VMs from the single set of tools that they are already using to manage the VMs.

Scope

As described above, changes are required in libvirt. Eventually the tools using libvirt will need to be updated to take advantage of the new features, but that is not within the scope of this work.

TODO

Completed

SCSI storage discovery and rescan are complete.

The creation and destruction of virtual HBAs using NPIV is complete.

How To Test

Use cases

Discover SAN storage

Provision a new logical unit on iSCSI or fibre channel storage. Use virsh to trigger a scan for it, and confirm that it appears correctly.

To discover logical units on a particular HBA, create a pool for that
HBA using:

where '1111222233334444:5555666677778888' is the WWPN:WWNN and host5
is the physical HBA you want to use to create the virtual HBA. If the
create is successful, you'll get a new HBA in the system with the next
available host number.

The libvirt API implementation is intended to be used by client
applications, but the functionality can be tested with virsh.

Creating a new virtual adapter using virsh is a two step process.
First, find the node device name of the HBA that's going to be used to
create the virtual adapter. You can get a list of all the HBAs on
your system with:

The parent element is the name of the parent HBA as listed by virsh
nodedev-list. wwpn and wwnn are, as you would expect, the WWNN and
WWPN for the virtual HBA to be created. Libvirt does not do any
validation of the WWPN/WWNN; invalid WWNs are rejected by the kernel
and libvirt reports the failure. The error reported by the kernel is
somewhat misleading, however:

Contingency Plan

Documentation

Release Notes

This functionality adds the ability in libvirt to discover storage on a per-SCSI-host basis and issue NPIV operations. This enables administrators to discover, configure and provision storage for virtual machines without having to use multiple tools.